To the Editor.—In view of your article "Big New Centrifuge Has Unique Characteristics" (224:1341, 1973), it is interesting to recall the report of Sir Benjamin Brodie, the great English surgeon (1783-1861)."It was in 1843 that the remarkable case of Mr. Brunel occurred. This gentleman (the engineer of the Great Western Railway, and designer of the monster steamship Great Eastern) was unlucky enough to inhale a halfsovereign with which he was playing conjuring tricks to amuse some children. Brodie gives in the Med Chir Trans (vol 26), a clear and concise history of the various steps taken to extract this small, slippery, heavy body from its position deep in the chest, in or near the right lung. These measures were ultimately crowned with success. First, the patient was put into a revolving frame, and his whole body inverted, head downwards. This caused the coin to drop into the larynx;